Electrolytic method of continuous sheet manufacture and apparatus therefor



Sept. 20, 1932.

G. A. REINHARDT ET AL ELECTROLYTIC METHOD OF CONTINUOUS SHEET MANUFACTURE AND APPARATUS THEREFOR Filed March 22. 1929 Patented Sept. 20, 1932 UNITED STATES, ATE OFFICE.

GUSTAV A. REINHARDT AND RIQHARD H. EURICH, OF YOUNGSTOWN, OHIO ELECTROLYTIC METHOD OF CONTINUOUS SHEET MANUFACTURE AND APPARATUS THEREFOR Application filed March-22, 1929. Serial No. 349,070.

Our ihyention relates to continuous electrolytic production ofrelatively thin sheets, of indefinite length and of any desired width, the principal object of the invention being to provide a satisfactory commercially opera-v tive method for the production of such sheets as well as apparatus suitable for the performance thereof.

While our invention lends itself to the production of both ferrous and non-ferrous sheets, it is particularly adapted for the production of the former and we will therefore refer herein more especially to its use for that purpose. Hitherto the commercial production of such sheets has involved a tedious series of rolling and like operations by means of which a billet containing suitable'amount of metal is gradually and progressively reduced to a sheet of the desired size and thickness. In accordance with our invention, however, the shebt is .directly and continuma formed either of-the ultimate desired width and thickness or else of slightly greater thickness so that it may readily be reduced to the ultimate desired thickness by one or more passes through suitable rolls which may also serve to impart desired physical characteristics or finish, or both,

To enable those skilled in the art to comprehend and practise our invention we will now describe one manner of performing ourmethod of electrolytically producing continuous sheets, reference being had to the accompanying drawing in which we have diagrammatically illustrated one form of apparatus suitable for the performance thereof, the single figure being'a transverse" vertical section through the apparatus with certain of the parts thereof hown in elevation.

In accordance with the preferred practice of our invention the formation of the sheet is effected by continuous electrolytic deposition of metal on a revolving cathode from an anode submerged in a suitable electrolyte and formed of ferrous materialand then stripping the deposit from the cathode in the form of a continuous sheet of indefinite length after removing at least a large portion of the hydrogen which is included or entrained within the metal as it is progressively deposited, and which if allowed to remain therein would prevent satisfactory stripping ofthe sheet as well as render the latter substantially unfit for immediate use or further finishing operations. More particularly and as shown in the drawing we provide a'tank or vat 1 of any I suitable construction and lined or otherwise protected if necessary from the action of the electrolyte to be employed and which (may desirably be a solution'of ferrous chloride or other ferrous salt, This tank is of greater length than the width of the sheet to be formed and is filled with the electrolyte E to a suitable depth. Disposed f;- within the 5 tank in such position that it will be to a large extent submerged by the electrolyte is a cylindrical mandrel 2, desirably a cast ironroll of relatively large diameter, for example ten feet or more, though under some circumstances mandrels of lesser diameter may be satisfactorily employed; to effect a saving in weight the mandrel may be hollow but its outersurface should be smoothly finished throughout its extent. This mandrel is mounted on a Horizontal shaft 3 in turn supported in suitable bearings (not shown) and arranged to be driven at a relatively low speed by suitable driving means so as to correspondingly rotate the mandrel in the so direction indicated by the arrow. The bearings or journals for the shaft 3 may be supported by the end walls of the tank or in any other suitable way and through them the necessary electrical connection with the sa mandrel, which acts as the cathode during the electrolytic formation of the sheet, may be conveniently effected. These connections,

as well as others hereinafter described, are not illustrated in the drawing since they may be effected in any of the several ways commonly practised in the electroplating art and which are well understood by those conversant therewith.

Within the tank is also disposedan anode 5; this anode is desirably curved in conformity with the surface of the mandrel and arranged .to extend adjacent thereto from'a point a little below that at which the mandrel enters the electrolyte to a point considerably beyond its vertical diameter and as the anode is of course approximately the same length as the mandrel substantially one-half the surface of the latter isthus in juxtaposition with the anode which when the deposited metal is toohe taken therefrom, as

is customary in the electrolytic deposition the anode is suitably connected to a source of direct current in any convenient way.

Thus as the mandrel is slowly revolved in the direction of the arrow while the current is flowing, metallic iron is progressively deposited on the surface of the mandrel as it moves past the anode sothat a continuous film or layer D of progressively increasing thickness is formed on themandrel which, after it is stripped from the mandrel as hereinafter described, constitutes the formed sheet S. This metallic iron deposit adheres quite tenaciously to the mandrel and we therefore provide means for loosening it therefrom, said means desirably comprising a roll 6 of a length approximating that of the ,mandrel but preferably of considerably smaller diameter. This roll is mounted on a suitably-journ aled shaft 7 extending parallel, with the mandrel shaft 3 and so disposed that the roll 6 will bear on the layer of deposited metal preferably substantially at the top of the mandrel; suitable means (not shown) are provided for driving the shaft 7 and in turn the roll 6 preferably in the opposite direction to the mandrel and means may also desirably be arranged for regulating the pressure of the'roll 6 upon the .layer of metal. The speed of rotation of the roll 6 is ordiharily so adjusted that its surface speed is somewhat different from that of the layer of metal passing beneath it with the result that the latter is loosened from the mandrel and the upper surface of the sheet or layer to some extent smoothed and polished thereby. Additionally for positively freeing the sheet from the mandrel we provide a stripper 8 comprising a. sharp edge at its forward end which extends beneath the roll between-the mandrel and the sheet so'as to raise the latter from the mandrel just after it leaves the roll; desirably the upper forward face of the stripper, which of course extends for the full length of the mandrel, is beveled rear- 3 wardly and upwardly so as to direct the sheet angularly upward away from the mandrel, from whence it is led to a reel or other suit ablef-mechanism'adapted to progressively receive it as it is discharged from the mandrel. As deposlted on the mandrel, the metal tion since the roll 6 or other means employed to. loosen the metal from the mandrel would crack or break up the deposit and thus prevent the formation of a continuous sheet. This shortness or brittleness of the metal is due principally to the presence of hydrogen which is included in the metal as it is deposited electrolytically upon the mandrel and we therefore provide means for removing all orat least the major portion of this hydrogen from the deposited metal before it is subjected to the stripping operation.

While the means provided for effecting this hydrogen removal may be of any character suitable for the performance of the intendedfunction, one form satisfactorily operative for the purpose comprises an electrode 10 desirably curved in conformity with the mandrel and disposed adjacent the surface of the latter below the point at which it leaves the electrolyte as it rotates. This secondary electrode is immersed in a portion E of the electrolyte which is disposed in a separate cell and thus kept apart from the major whose free edge turnslup against the sur-' face of the metal deposit on the mandrel and forms a substantially liquid tight seal at this point so as to prevent any material mixing of the electrolyte E above the partition with the major portionof the electrolyte E in the tank. The electrode 10 is so electrically connected that its potential is negative as respects the mandrel and deposit D thereon whereby as the mandrel moves past the electrode a reversal of the current flow is effected and the major portionof the hydrogen in the deposited metal as well as a small amount of the deposited metal itself is carried over to the electrode and the balance or major portion of the deposited metal on the m. drel thus freed from the gas so that it leaves the electrolyte substantially devoid thereof.

\Ve also prefer to arrange a flash anneal ing mechanism above the tank in such posi= tion that a hot flame projected by this mechanism will play across the width of the surface of the deposited metal before the latter reaches the roll 6; this flash annealing mechanism, generally designated as 14 and which may beof any suitable construction, extends substantially the full length of the mandrel and performs to some extent a double function. namely, that of removing any residual hydrogen which may not have been removed by the action of the electrode 10 and of antate the stripping operation. While we premandrel a suitable alternating current as has fer to employ both the .electrode 10 and flash annealing mechanism as described, in some cases either one or the other may be found suflicient to remove enough hydrogen from the metalto permit it to be stripped from the mandrel.

It is also possible to effect removal of the hydrogen either in conjunction with the flash annealing mechanism or without it by impressing on the direct current utilized to effect the deposition of metallic iron on the heretofore sometimes been practised in the plating art and we therefore contemplate the use of this method of removing the hydrogen under conditions which might make the same desirable and include the same Within the scope of our invention. Of course when this method of hydrogen removal is employed the electrode 10 and partition 11 or other means utilized to form a separate cell for its reception will ordinarily be omitted.

As it is believed the manner of practising. our improved method of. electrolytically forming continuous sheets by the use of an apparatus such as we have described will be readily apparent from the foregoing, extended reference thereto would be superfluous. It should be noted, however, that sufficient metal to form a sheet of the .desired thickness must be deposited on the mandrel between the time when any given point thereon receives its initial deposit which occurs when the point is-adjacent the upper end of .the anode 5, and the time when it passes from the depositing zone near the other end of the anode; consequently, the rotational speed of the mandrel must therefore be adjusted to efiect this result under the particular conditions as to current strength and the like which may be present. Additionally, depending on how much of the deposited metal is removed through the operation of the electrode 10 if employed, some allowance may also have to be made for a corresponding reduction in thickness of the deposit resulting therefrom and therefore, where the amount of metal so removed is appreciable, it is requisite that the thickness of the deposit be fore this removal is effected be slightly greater than the desired ultimafi; thickness of the sheet.

Although we have herein morej iarticular- 1y referred to the use of our invention in the electrolyte and an anode of proper material, our invention may be employed with equal facility for the production of non-ferrous sheets. Thus, for example,-a solution of zinc salt may be used as the electrolyte in conjunction with a soluble zinc anode instead of .a ferrous anode to produce a continuous zinc sheet, or a suitable solution of zinc salt in conjunction with a lead or other anode insoluble therein may also be employed fora similar purpose, the deposited metal in that case being abstracted from the solution instead of from the anode.

Moreover, while we have herein described one manner of performing the invention together with apparatus suitable therefor, we

do not thereby desire or intend to specifically confine or limit ourselves thereto as modifications may be made in the method itself and changes and variations in the construc tional details of the apparatus may also be effected if desired without departing from thespirit and scope of theinvention as defined in the appended claims.

Having thus described our invention, we claim and desire to protect by Letters Patent of the United States:

1. The method of forming a metallic sheet of indefinite length which comprises the steps of forming an electrolytic metallic deposit progressively on the face of a mandrel rotating in. an electrolyte until the deposit attains a predetermined thickness, thereafter removing included hydrogen from the deposited metal and then immediately remov-' ing the latter from the electrolyte and strip ping it from the face of the mandrel as a continuoussheet. i

2. The method of forming a ferrous sheet of indefinite length which comprises the steps of rotating a cylindrical mandrel in an electrolytic bath, forming an electrolytic deposit of ferrous metal on the face of the mandrel progressively as it moves through the electrolytic bath containing an anode, forming an electrolytic deposit of progressively increasing thickness on the face of the mandrel as it moves past the anode, effecting removal of included hydrogen from the deposit electrolytically after obtaining its desired thickness, removing the dehydrogenized deposit from the electrolyte, then loosening the deposit from the mandrel by application of roll pressure and finally stripping the deposit from the mandrel as a contlnuous sheet.

4. The method of forming a ferro s sheet of indefinite length which comprlses the j steps of rotating a cylindrical mandrel adj acent an anode and an electrode respectively disposed in separate cells, forming an electrolytic deposit of ferrous metal on the sur cell, a cylindrical mandrel of relatively large diameter adapted for artial immersion in and rotationthrough t e electrolyte in the cell, an anode disposed in the cel adjacent the face of the mandrel, electric connections between the anode, mandrel and a source of direct current, means for removing'included hydrogen from metal deposited on the face of the mandrel comprising an electrode disposed adjacent the mandrel and beneath the surface of the electrolyte and heatin means disposed adjacent the mandrel a ove the surface of the electrolyte, means for loosening the deposited metal from the mandrel after said hydrogen removal, ahd means for there after stripping the deposited metal from the 'mandrelas 'a continuous sheet.'

6. In apparatus for electrolytic formation le cylindrical mandreli a vat partially enclosing said man;

of continuous sheets, a rotata drel an forming in combination therewith separate cells respectively" adapted to contain ane'lectrolyte, an anode disposed in that cell first traversed by the surface'of the man- 4 drel as it rotates, an electrode disposed in the other cell, means disposed between the cellsoperative to prevent passage of the electrhlyte-therebetween, a roll disposed above stripping means in the rear of the roll oper- I ative to strip the loosened layer of metal from the mandrel as a continuous sheet;

the mandrel and arranged to bear vertically wherebycurrent'is caused to flow through the electrolyte between said electrode and themandrel, a roll dis osed above the man'- drel and arranged to ear vertically dow-nward thereon to loosen the layer of deposited metal as it moves under the roll, and stripping means in the rear of the roll 0 erative to strip the loosened layer of metal rom the mandrel as acontinuous sheet.

8. In apparatus for electrolytic formation of continuous sheets, a e lindrical mandrel arranged to rotate throug I separate bodies of electrolyte, an anode immersed inthe first of said bodies encountered by the mandrel as it rotates and having a given potential with res set to the mandrel, an electrode immerse opposite potential with respect to the mandrel, a rolldisposed above the mandrel and operative to'bear' on the surface of the layer of metal deposited on the mandrel during its of metal from the mandrel as a continuous sheet after it has been acted upon by the roll, said electrode being 0 erative to abstract included hydrogen from t e deposited metal vin the other body and having an passage through the first body of electrolyte P and after its emergence from the second body during its passage through the second body of electrolyte.

In witness whereof, we have hereunto set our hands this 19th day of March, 1929.

' GUSTAV A. REINHARDT. RICHARD H. EURICH.

7. In apparatus for eleetrol ic formation I a of continuous sheets,.a rotata 1e cylindrical mandrel, a vat partially enclosing said mandrel and forming in combination therewith separate cells respectively adapted to contain an electrolyte, an anode disposed in that cell first traversed by the surface of the mandrel as it rotates and having a positive 0- tential with respect to the mandrel, an. e ectrode disposed i'nzthe other cell and connected to the mandrel through a'source of current 

